Management of ventricular tachycardia (VT) storm in a
patient with an implantable cardioverter-defibrillator (ICD) is a
challenging medical emergency. We describe a patient with cardiac
sarcoidosis (CS) and an ICD who is admitted with VT storm. Management
of VT was difficult due to resistance to multiple antiarrhythmic drugs.
He responded to immunosuppressive therapy supporting active CS as the
cause of his VT. This case suggests that CS may underlie some cases of
refractory VT and that immunosuppressive therapy may be effective in
controlling this arrhythmia.

Key words: Cardiac
Sarcoidosis; VT Storm.

Introduction

Sarcoidosis is a disease of unknown etiology and protean
manifestations. Cardiac involvement is not uncommon. Rhythm
disturbances are an important manifestation and can lead to sudden
cardiac death. We report a patient with CS who presented with
ventricular tachycardia storm resistant to traditional antiarrhythmics.
He responded well to corticosteroids and methotrexate.

Case Report

A 46-year-old male with hypertension, type 2 diabetes mellitus and
obstructive sleep apnea was diagnosed histologically with pulmonary
sarcoidosis 5 years previously. He was treated with oral prednisone
tapered over 6 months. Three years later, he developed Mobitz 1
second-degree atrioventricular block. Six months after that he
developed congestive heart failure (CHF) with left ventricular ejection
fraction (LVEF) of 40%. A coronary angiogram did not reveal any
significant stenosis. Cardiac MRI showed concentric left ventricular
hypertrophy with hyperenhancement. Endomyocardial biopsy confirmed
extensive myocardial sarcoidosis. (Figure
1). He had progressive decline of his LVEF to 20% and developed
left bundle branch block (QRS 165 msec). He was treated with oral
prednisone 60mg daily. In light of functional class III CHF despite
optimal medical therapy, a cardiac re-synchronization ICD (Medtronic
Concerto CI54DWK) was implanted. Over the next two months, he received
six shocks for sustained VT and was placed on sotalol 120 mg twice
daily with continued oral steroid therapy. His CHF symptoms improved
and arrhythmia was under control.

Five months after CRT-D implantation, he was admitted with multiple
episodes of VT despite being on oral prednisone 30 mg daily and
sotalol. He was treated successfully with antitachycardia pacing 56
times, and he was cardioverted 12 times over the course of 24 hours. VT
was right bundle inferior axis with negative precordial concordance
suggesting an apical origin. All episodes of VT were of similar
morphology with a cycle length of 300 mSec. Lidocaine, mexiletine and
amiodarone reduced the frequency of sustained VT episodes, but he
continued to have episodes of symptomatic non-sustained VT. LVEF was
15-20%. A whole body gallium scan demonstrated uptake in the heart
consistent with exacerbation of cardiac sarcoidosis (Figure 2). High dose intravenous
steroid therapy (methylprednisolone 60 mg every 6 hours) was initiated
in place of chronic oral steroid therapy and VT resolved within 12
hours. Oral methotrexate was added as a steroid sparing strategy.
Sotalol was continued and other antiarrhythmics were stopped. Three
days later, he was discharged on methotrexate (15mg/week PO) and a
tapering dose of oral prednisone. At 3 and 6 months follow-up visits,
his CHF was compensated with an LVEF of 25-30% and he was free of
ventricular tachycardia on device interrogation. Repeat gallium scan at
6 months showed no significant uptake in the heart.

Management of arrhythmias in CS is difficult and effective control of
VT often is not achievable by a single method of therapy. Acute
inflammation with new granuloma formation that can disrupt myocardial
fibers together with the patchy scarring associated with old healed
granulomas can provide a substrate for new VT reentrant circuits.
Antiarrhythmic drugs can facilitate occurrence of VT, as well as
aggravate conduction abnormalities. Hypercalcemia, inherent to
sarcoidosis; hypokalemia from concurrent corticosteroid use, as well as
the interaction between acute phase reactants and antiarrhythmics can
further complicate drug therapy [1].

Optimal therapy of ventricular arrhythmia associated with CS is not
well established. Various regimens including corticosteroids,
antiarrhythmic medications, ICDs and catheter ablations have been
attempted. Steroids improved overall mortality in CS [2]. Steroids are
believed to be capable of attenuating the inflammatory response and
slowing subsequent fibrosis. Although corticosteroids help in
suppressing arrhythmia secondary to sarcoid exacerbation, they may be
of little use in the management of VT from scarred myocardium. This can
explain the recurrence of VT despite treatment with corticosteroids in
previously reported cases [3-4]. Active sarcoid exacerbation may cause
VT in patients who are already on treatment with moderate to high doses
of corticosteroids as seen in this patient. Immunosuppressive therapies
are recommended as a steroid sparing strategy in the management of
sarcoidosis and can be beneficial in controlling arrhythmia.

A stepwise approach in the management this malignant arrhythmia was
studied [5]. ICD implantation, immunosuppression with corticosteroids,
then up to two antiarrhythmic drugs were used (in that order) before
patients were taken to the EP lab for mapping and ablation. 9 of the 21
patients with sustained VT underwent ablation. 44 VTs were induced and
31 were ablated. VT burden was reduced more than 98% in the first 3
months post ablation. The mechanism of VT in virtually all patients was
re-entry [5-6].

Cardiac Resynchronization Therapy (CRT), which is an adjunct treatment
to pharmacological therapy in patients with advanced heart failure, may
have potential proarrhythmic effects [7]. Although rare, CRT has been
shown to cause VT [8] and electrical storm [9]. Most CRT associated
ventricular proarrhythmia was seen in ischemic cardiomyopathy patients
soon after biventricular pacing lead implantation, and improved with
cessation of biventricular pacing [8-9]. This patient tolerated CRT
well for months. The presence of extensive myocardial sarcoidosis and
lack of recurrent VT during the follow-up period despite continued CRT
makes CRT related proarrhythmia an unlikely mechanism of VT in our
patient. Electrophysiology study with ablation can be undertaken in CS,
but VT circuits can change as inflammation waxes and wanes. VT may be
ablated only to reoccur as the substrate shifts. Ablation should be
considered as an option in those patients with recurrent VT that are
unresponsive to antiarrhythmic and immunosuppressive drugs.

Conclusion

Cardiac sarcoidosis related arrhythmia can be very difficult to manage.
Because of increased awareness of the risk of sudden cardiac death and
early ICD implantation, CS patients can survive to present with VT
storm, which is not uncommonly resistant to standard antiarrhythmic
drugs. While corticosteroids are mainstay of therapy to control the
acute inflammation and hence related arrhythmia, immunosuppressive
therapy such as methotrexate should be considered early if steroid
resistance develops and before proceeding to catheter ablation.